1. Field of the Invention
This invention relates to electrical relay apparatus. In particular, it relates to the construction of miniature electromechanical relays intended for use on circuit boards.
2. Description of the Prior Art
Electromechanical relays have found wide and varied applications in the Telecommunications and Electronics Industry. Although solid state devices have recently replaced relays in many telecommunication and electronic systems, electromechanical relays still offer many advantages in terms of cost and reliability in electrical circuit applications.
Electromechanical relay constructions generally comprise an electromagnetic structure, armature and contact spring assembly wherein the energization of the electromagnetic structure actuates the armature to control the operation of the contact spring assembly thereby engaging and disengaging contacts to control external electrical circuitry coupled with the relay. In modern technology, miniaturization of components have resulted in large numbers of components being mounted on circuit boards. Since space on circuit boards is at a premium, electromechanical relays have been reduced in size so as to require only a small amount of mounting space on a circuit board. As the size of components have decreased and the number of electrical circuits appearing on a circuit board increased, the electrical current requirements for circuit boards have also been decreased thereby requiring the development of low current electromechanical relays.
A problem arises in the development of miniature and low current electromechanical relays in that the operating sensitivity of an electromechanical relay is affected by the reduction in size of the relay electromagnetic structure and the amount of electrical current required to activate the relay armature.
Accordingly, a need exists for a miniature low current electromechanical relay having a high degree of operating sensitivity. A need also exists for an electromechanical relay requiring a small mounting space on a circuit board and a small amount of electrical current to engage and disengage contacts for controlling external electrical circuitry.